Both paths can be used to reliably upload the required test files. Although the progress status for (1) operates sucessfully, that for (2) remains 'stuck' on 0% even after file upload has completed.

Looking at our client-side WireShark traces for your .NET control's upload on each run we note the successful establishment of 3x HTTPS connections, one (apparently) being reserved purely for the data upload itself.

For path (2) one of the other 2 connections consistently fails to actually contain any ‘Application Data’ packets. It would thus be very useful if you could help us to achieve a better understanding of the purpose of the 2 non-data upload HTTPS connections, whilst our review of the traces continues...

While FileUploader.NET is still for sale, it is no longer a supported product of ours. Our existing support documentation and forums are an excellent source of support information, however our support team will not handle additional questions regarding support of this product. Because this is a sunset product, development (including any possible bug fixes) has ceased. However, we do offer the source code version of the product to allow you to make additional changes. This version has been on the market for a year and a half and we have had no major support issues with it, proving that it is a very stable product.